The present disclosure is related to winding cores, and more particularly is related to winding cores for materials including but not limited to plastic non-shrink film, plastic shrink film, yarns, and other elastic materials that are wound under tension such that the material is in an elastically stretched condition when wound about the core and/or shrinks after being wound about the core, resulting in substantial and continuing radially inward pressure on the core.
In the winding of such materials, the roll of wound material stores energy referred to herein as “roll strain energy” because of the tension under which the film is wound around the core and/or because of the shrinkage of the material after winding. This mechanism is analogous to a spring which, when deformed, stores energy. Conversely, when the deformation in the spring is relieved, the stored energy in the spring is reduced. Wound roll structures having high roll strain energy significantly compress the core OD, causing a reduction in the inside diameter of the core, referred to herein as “ID comedown”. Additionally, the compressive load from the roll also causes the core to grow in length. These effects can lead to problems in the field.